Optically pumped quantum M_x-M_R magnetometer with high oscillating magnetic field

A dip of the transverse component of the magnetic moment as a function of resonance frequency-detuning will emerge when the intensity of oscillating magnetic field exceeds a specific value, which is demonstrated theoretically and experimentally. The linewidth of magnetic-resonance signal can be much smaller than when the Mx–MR magnetometer operates on condition that the intensity of oscillating magnetic field is smaller than this specific value, and the Mx–MR magnetometer can possess a much higher signal-to-noise ratio. The experimental result shows that the sensitivity of Mx–MR magnetometer can be improved by an order of magnitude under this condition.     

Optically pumped quantum M X magnetometers: Digital measurement of the M X resonance frequency in a rapidly varying field

A new way of digitally constructing a phase-locked loop for an optically pumped quantum M _X magnetometer is suggested. It provides a high accuracy and speed of magnetic resonance frequency tracking in a rapidly varying field.     

Experimental demonstration of the sensitivity of an optically pumped quantum magnetometer

The sensitivity σ of an optically pumped quantum magnetometer is measured directly by comparing the output frequencies of ⁸⁵Rb and ⁸⁷Rb magnetometers integrated in a single two-isotope cell. The result σ₈₇=59.6±6 fT Hz^−1/2 agrees well with the value σ ₈₇ ^light =53.7±2 fT Hz^−1/2 obtained indirectly by measuring 87 the ratio of the resonance steepness to the shot noise of light.     

Optically pumped GaN/AlGaN quantum well intersubband terahertz laser

We propose an optically pumped nonpolar GaN/AlGaN quantum well (QW) active region design for terahertz (THz) lasing in the wavelength range of 30 μm～ 40 μm and operating at room temperature. The fast longitudinal optical (LO) phonon scattering in GaN/AlGaN QWs is used to depopulate the lower laser state, and more importantly, the large LO phonon energy is utilized to reduce the thermal population of the lasing states at high temperatures. The influences of temperature and pump intensity on gain and electron densities are investigated. Based on our simulations, we predict that with a sufficiently high pump intensity, a room temperature operated THz laser using a nonpolar GaN/AlGaN structure is realizable.     

Optically pumped far-infrared laser with sandwich resonator

A new resonator geometry for optically pumped far-infrared lasers is suggested. First experimental results of a transversely pumped CW laser are reported.     

Zero field optically pumped magnetometer with independent dual-mode operation

We propose a dual-mode optically pumped magnetometer(OPM) that can flexibly switch between single-beam modulation mode and double-beam DC mode.Based on a 4 mm × 4 mm ×4 mm miniaturized vapor cell,the double-beam DC mode achieves a sensitivity of 7 fT/Hz^1/2 with probe noise below 4 fT/Hz^1/2 and working bandwidth over 65 Hz.This mode is designed to precisely measure the noise floor of a mu-metal magnetic shield.The single-beam modulation mode(sensitivity20 fT/Hz^1/2...     

Optically pumped FIR-laser with variable Fabry-Perot output coupler

An optically pumped FIR laser was operated with a copper mesh Fabr-Perot output coupler. With this device a Gaussian output beam was obtained andthe degree of coupling could be varied continuously, thus allowing optimum coupling. From the measured properties of the wire mesches grains of two FIR laser lines are calculated and the saturation intensities estimated.     

Optically pumped submillimetre laser action in formaldoxime and ammonia

Strong submillimetre laser action has been obtained on five lines of a new laser gas, formaldoxime. Several new emission lines have also been produced by isotopic CO₂ laser pumping of¹⁴NH₃ and¹⁵NH₃. One of these lines at 102.9 m is a rotation-inversion transition in the 2v ₂ state, and is the first example of cw laser action in such a highly excited state.     

Gradiometric investigation of a cesium-vapor quantum magnetometer

Experiments aimed to determine the sensitivity and the optical shift of the output frequency of a magnetometer based on optical pumping of cesium atoms and intended for a neutron magnetic resonance stabilization system are described. A gradiometric arrangement used in these experiments makes it possible to reduce the effect of magnetic field variations on measurements.     

Optically pumped distributed feedback thin film waveguide lasers with multiwavelength and polarized emissions

Zirconia titania organically modified silicate (ZrO₂-TiO₂-ORMOSIL) thin film waveguides of thickness from 0.4 to 7.0 μm were synthesized using low temperature sol–gel method. Narrow linewidth distributed feedback (DFB) lasing was demonstrated in rhodamine 6G-doped ZrO₂-TiO₂-ORMOSIL waveguides. Simultaneous tuning of multiple-output wavelengths was achieved in the dye-doped waveguides by varying the period of the gain modulation generated by a nanosecond Nd:YAG laser at 532 nm. As many as eight separate output wavelengths were observed for a planar ZrO₂-TiO₂-ORMOSIL waveguide of thickness 7.0-μm. The output polarizations of the DFB waveguide lasers can be tuned by varying the polarization of the crossing pump beams. TE and TM optical waves belonging to the same propagation mode were generated by crossing two polarized pump beams, resulting in an effective double of the number of output wavelengths. Continuous tuning of the polarized laser outputs was also achieved by varying the crossing angle.     

Optically pumped terahertz lasers with high pulse repetition frequency: theory and design

Optically pumped terahertz （THz） lasers with high pulse repetition frequency are designed. Such a laser includes two parts： the optically pumping laser and the THz laser. The structures of the laser are described and analyzed. The rate equations for the pulsed THz laser are given. The kinetic process and laser pulse waveform for this kind of laser are numerically calculated based on the theory of rate equations. The theoretical results give a helpful guide to the research of such lasers.     

Measurement of magnetic susceptibility with the aid of a quantum magnetometer

A procedure is proposed for the measurement of magnetic susceptibility with the help of a quantum magnetometer without the use of reference materials. Computational formulas are given for samples of various diameters and lengths. A number of specific recommendations are given for the choice of the optimal configuration for the flux transformer, the measuring ampul, and the samples.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 40–49, February, 1984.The author is grateful to N. I. Alekseev, I. E. Kuznetsov, and M. V. Krasheninnlkov for help in performing this research.     

Optically pumped GaAs waveguide lasers with a fundamental 0.11 μ corrugation feedback

Surface corrugations with a period of 0.115 μ were ion-milled on GaAs dielectric waveguides. Laser action was observed under optical pumping. Single mode as well as multimode oscillation was obtained under different pumping conditions.     

Optically implementable designs of reversible sequential devices

We have proposed some new designs of reversible sequential circuits using NCT gate library and compared them with the earlier proposals. It has been shown that the present proposals have lower gate complexities and lower number of garbage bits compared to the earlier proposals. We have addressed some conceptual issues related to the feedback and the choice of gate library. Further it is shown that the proposed quantum / reversible circuits can be implemented optically.     

Optically pumped polarized H− ion sources for RHIC and HERA colliders

Optically-Pumped Polarized Ion Sources (OPPIS) are based on polarization transfer collisions between hydrogen (or deuterium) ions and an optically-pumped electron spin polarized alkali metal vapor. The results of studies on optical pumping of high density alkali metal vapour and spin exchange and charge-exchange polarization transfer collisions are discussed. The results of high current OPPIS development for Relativistic Heavy Ion Collider (RHIC), BNL and HERA, DESY are also presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

Feasibility study of optically pumped molecular lasers with small quantum defect

An analytical analysis of continuous wave (CW) optically pumped molecular lasers with small quantum defect is presented. The results show the conditions under which lasing with small Stokes shifts are possible. The general results are applied to HCN as an example gas. The predictions from the analytical approach are in good quantitative agreement with numerical calculations. The effective vibrational lifetimes and rotational relaxation rates of the molecule determine the principal behavior of such lasers. High overall laser efficiencies are possible for long interaction length of pump laser and gas media, which for example can be achieved in waveguide structures. This makes such lasers potentially interesting for coherently combining the output of mutually incoherent fiber and or diode lasers.     

Optically gated resonant emission of single quantum dots

We report on the resonant emission in coherently driven single semiconductor quantum dots. We demonstrate that an ultraweak nonresonant laser acts as an optical gate for the quantum dot resonant response. We show that the gate laser suppresses Coulomb blockade at the origin of a resonant emission quenching, and that the optically gated quantum dots systematically behave as ideal two-level systems in both regimes of coherent and incoherent resonant emission.